use pathfinders for usa, since they can snipe the occupants of the stinger site far and concealed. Also use tomahawk. Use the emp tank for china to avoid your forces getting hit by rockets. For gla use scud launcher or rocket buggy for ranged attacks.

Auroras 2 of them can hit stingers and evade them using countermeasures or the airforce general's laser point defense. Stealth fighters can also do the job.

Park some avengers near the stingers, then take them out with planes or humvees filled with rocket men or whatever, you might need to protect the avengers though, but they should destroy all the rockets.

If you play with the USA Airforce general, then laser defences should be more than enough to keep missiles off your planes. If that doesn't work upgrade countermesures as well

use infantry upgraded with flahbang gernades flow in with choppers to take out the stingers.